1. Field of the Invention
This invention relates to a class of sulfonamide derivatives having substituted thereon an (optionally substituted) phenoxybenzoate moiety, which compounds exhibit unexpectedly desirable pre- and post-emergent herbicidal activity. In other aspects, this invention relates to a herbicidal composition comprising such novel compounds as well as to a method of controlling the growth of undesirable plants, such as weeds, employing the novel herbicides of this invention. In yet another aspect, this invention relates to a process for producing such compounds.
Weeds compete with crops for light, moisture, nutrients and space. Thus, weeds inhibit the production of foliage, fruit or seed of agricultural crops. The presence of weeds may also reduce the quality of the harvested crop and reduce harvesting efficiency. Weed control is essential for maximum production of many agronomic and horticultural crops including corn, (Zea mays L.), cotton (Gossypium SP), sunflower (Hellianthus annus L.) and soybeans (Glycine max (L.) Merr.). Weeds on noncropped areas may cause a fire hazard, undesirable drifting of sand or snow, or irritation to persons with allergies. Thus, suppression of undesirable weed growth is very advantageous.
While a large number of compounds possessing herbicidal activity are known, it would be nonetheless desirable to possess additional compounds which would effectively control the growth of unwanted vegetation.
2. Description of Related Art
U.S. Pat. No. 4,465,508 discloses certain substituted diphenyl ethers useful as herbicides. Somewhat similar herbicidal substituted diphenyl ethers are disclosed in Chemical Abstracts 102:131714h (1985); 102:166479n (1985); 102:61941d (1985); 101:191337b (1984); 101:90771h (1984); and U.S. Pat. Nos. 4,744,812 and 4,744,818. Finally, U.S. Pat. No. 4,452,629 discloses certain N,N'(thio)-5(substituted-phenoxy or pyridyloxy)-2-substituted benzoic acid sulfonamides and sulfamidoyl fluoride derivatives which exhibit herbicidal activity.
However, the compounds disclosed in the above references differ significantly in structure from the N,N-bis [benzyl-phenoxy] sulfonamides of the present invention.